Autoantibodies from vasectomized guinea pigs inhibit fertilization in vitro.

Immunoglobulin G and Fab antibodies were isolated from the serum of vasectomized guinea pigs, and the effects of the antibodies on fertilization in vitro were investigated. These antibodies had profound inhibitory effects on (i) sperm-to-sperm adhesion, (ii) the acrosome reaction, (iii) sperm-zona binding, and (iv) sperm-ovum fusion. This finding may explain certain cases of infertility after vasovasostomy in men.